1. Field of the Invention
The present invention relates to a wiring board having a wiring layer formed in multiple layers, a method of manufacturing such wiring board, and an electronic device having such wiring board.
2. Background Information
Conventionally, wiring boards are manufactured by forming a wiring layer and an insulating layer simultaneously on the surface of a substrate. First, droplets of both a conductive material for forming the wiring layer and an insulating material for forming the insulating layer are deposited onto the surface of the substrate by ink jetting. Then, the wiring layer and the insulating layer are formed simultaneously on the surface of the substrate as one layer. Thereafter, another layer of a wiring layer and an insulating layer is formed by similar methods on top of the layer already formed. Thus, a wiring board having multiple layers of the wiring layer is obtained. The wiring layers are electrically conductive relative to each other. Japanese Patent Application Publication No. 11-163499 discloses an example of such wiring board.
In other words, the conventional technique entails forming the wiring layer and the insulating layer simultaneously as one layer by ink jetting, and curing the layer by heating or the like. Consequently, it is difficult to use the two materials together when the heating temperatures at which the conductive material and the insulating material are deposited onto the surface of the substrate are different, or when the curing methods for the two materials, such as with heating and ultraviolet ray irradiation, for example, are different. Also, the wiring layer and the insulating layer formed by ink jetting do not have a high density, unlike the high-density wiring boards formed by conventional additive methods or the like.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for improved wiring board, method of manufacturing wiring board, and electronic device having such wiring board that overcome the problems of the conventional art. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.